LITHIUM ION ELECTROCHEMICAL CELL, WITH IMPROVED SEALING

The invention relates to a lithium-ion electrochemical accumulator-or Li-ion battery-having improved leak tightness of the liquid electrolyte contained therein. The architecture of the accumulator may be monopolar or bipolar. According to the invention, the sealing of the liquid electrolyte contained in the accumulator is improved through the presence of a leak-tight device or a plurality of leak-tight devices comprising a polymer that, in contact with the liquid electrolyte, converts to a gel in which the electrolyte is trapped and immobilised. Applications: any field in which Li-ion batteries of monopolar or bipolar architecture are likely to be used, and in particular in the manufacture of electric or hybrid vehicles and portable electronic devices (telephones, touchpads, computers, cameras, camcorders, etc).